<!doctype html>
<html lang="en" class="no-js">
  <head>
    <meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<meta name="generator" content="Hugo 0.74.3" />

<META NAME="ROBOTS" CONTENT="NOINDEX, NOFOLLOW">

<link rel="alternate" type="application/rss&#43;xml" href="https://kubernetes-sigs.github.io/kustomize/api-reference/glossary/index.xml">


<link rel="shortcut icon" href="/favicons/favicon.ico" >
<link rel="apple-touch-icon" href="/kustomize/favicons/apple-touch-icon-180x180.png" sizes="180x180">
<link rel="icon" type="image/png" href="/kustomize/favicons/favicon-16x16.png" sizes="16x16">
<link rel="icon" type="image/png" href="/kustomize/favicons/favicon-32x32.png" sizes="32x32">
<link rel="icon" type="image/png" href="/kustomize/favicons/android-36x36.png" sizes="36x36">
<link rel="icon" type="image/png" href="/kustomize/favicons/android-48x48.png" sizes="48x48">
<link rel="icon" type="image/png" href="/kustomize/favicons/android-72x72.png" sizes="72x72">
<link rel="icon" type="image/png" href="/kustomize/favicons/android-96x96.png" sizes="96x96">
<link rel="icon" type="image/png" href="/kustomize/favicons/android-144x144.png" sizes="144x144">
<link rel="icon" type="image/png" href="/kustomize/favicons/android-192x192.png" sizes="192x192">

<title>Glossary | Kustomize</title><meta property="og:title" content="Glossary" />
<meta property="og:description" content="Glossary of terms
" />
<meta property="og:type" content="website" />
<meta property="og:url" content="https://kubernetes-sigs.github.io/kustomize/api-reference/glossary/" />
<meta property="og:site_name" content="Kustomize" />
<meta itemprop="name" content="Glossary">
<meta itemprop="description" content="Glossary of terms
">
<meta name="twitter:card" content="summary"/>
<meta name="twitter:title" content="Glossary"/>
<meta name="twitter:description" content="Glossary of terms
"/>





<link rel="preload" href="/kustomize/scss/main.min.818a933df0186c907f1faea6730835dd5fa01c3b53af36bb68396dc80a2d3c45.css" as="style">
<link href="/kustomize/scss/main.min.818a933df0186c907f1faea6730835dd5fa01c3b53af36bb68396dc80a2d3c45.css" rel="stylesheet" integrity="">


<script
  src="https://code.jquery.com/jquery-3.3.1.min.js"
  integrity="sha256-FgpCb/KJQlLNfOu91ta32o/NMZxltwRo8QtmkMRdAu8="
  crossorigin="anonymous"></script>



<link rel="stylesheet" type="text/css" href="https://kubernetes-sigs.github.io/kustomize//css/asciinema-player.css" />

    <title>Glossary | Kustomize</title>
  </head>
  <body class="td-section">
    <header>
      
<nav class="js-navbar-scroll navbar navbar-expand navbar-dark flex-column flex-md-row td-navbar">
        <a class="navbar-brand" href="/kustomize/">
		<span class="navbar-logo"></span><span class="text-uppercase font-weight-bold">Kustomize</span>
	</a>
	<div class="td-navbar-nav-scroll ml-md-auto" id="main_navbar">
		<ul class="navbar-nav mt-2 mt-lg-0">
			
			
			<li class="nav-item mr-4 mb-2 mb-lg-0">
				
				
				
				
				
				
				<a class="nav-link" href="/kustomize/installation/" ><span>Installation</span></a>
			</li>
			
			<li class="nav-item mr-4 mb-2 mb-lg-0">
				
				
				
				
				
				
				<a class="nav-link" href="/kustomize/guides/" ><span>Guides</span></a>
			</li>
			
			<li class="nav-item mr-4 mb-2 mb-lg-0">
				
				
				
				
				
				
				<a class="nav-link active" href="/kustomize/api-reference/" ><span class="active">API Reference</span></a>
			</li>
			
			<li class="nav-item mr-4 mb-2 mb-lg-0">
				
				
				
				
				<a class="nav-link" href="https://github.com/kubernetes-sigs/kustomize/tree/master/examples" target="_blank" ><span>Example</span></a>
			</li>
			
			<li class="nav-item mr-4 mb-2 mb-lg-0">
				
				
				
				
				
				
				<a class="nav-link" href="/kustomize/faq/" ><span>FAQ</span></a>
			</li>
			
			<li class="nav-item mr-4 mb-2 mb-lg-0">
				
				
				
				
				
				
				<a class="nav-link" href="/kustomize/blog/" ><span>Blog</span></a>
			</li>
			
			<li class="nav-item mr-4 mb-2 mb-lg-0">
				
				
				
				
				
				
				<a class="nav-link" href="/kustomize/contributing/" ><span>Contributing</span></a>
			</li>
			
			
			
			<li class="nav-item dropdown d-none d-lg-block">
				

<a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
	English
</a>
<div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
	
	<a class="dropdown-item" href="/kustomize/zh/api-reference/glossary/">简体中文</a>
	
</div>
			</li>
			
		</ul>
	</div>
	<div class="navbar-nav d-none d-lg-block">
</div>
</nav>

    </header>
    <div class="container-fluid td-outer">
      <div class="td-main">
        <div class="row flex-xl-nowrap">
          <div class="col-12 col-md-3 col-xl-2 td-sidebar d-print-none">
            




<div id="td-sidebar-menu" class="td-sidebar__inner">
  
  <form class="td-sidebar__search d-flex align-items-center">
    

    <button class="btn btn-link td-sidebar__toggle d-md-none p-0 ml-3 fas fa-bars" type="button" data-toggle="collapse" data-target="#td-section-nav" aria-controls="td-docs-nav" aria-expanded="false" aria-label="Toggle section navigation">
    </button>
  </form>
  
  <nav class="collapse td-sidebar-nav pt-2 pl-4" id="td-section-nav">
    
    <div class="nav-item dropdown d-block d-lg-none">
      

<a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
	English
</a>
<div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
	
	<a class="dropdown-item" href="/kustomize/zh/api-reference/glossary/">简体中文</a>
	
</div>
    </div>
    
    






<ul class="td-sidebar-nav__section pr-md-3">
  <li class="td-sidebar-nav__section-title">
    <a  href="/kustomize/api-reference/" class="align-left pl-0 pr-2 td-sidebar-link td-sidebar-link__section">API Reference</a>
  </li>
  <ul>
    <li class="collapse show" id="kustomizeapi-reference">
      
      
      
      
      






<ul class="td-sidebar-nav__section pr-md-3">
  <li class="td-sidebar-nav__section-title">
    <a  href="/kustomize/api-reference/kustomization/" class="align-left pl-0 pr-2 collapsed td-sidebar-link td-sidebar-link__section">kustomization.yaml</a>
  </li>
  <ul>
    <li class="collapse " id="kustomizeapi-referencekustomization">
      
      
      
      
      






<ul class="td-sidebar-nav__section pr-md-3">
  <li class="td-sidebar-nav__section-title">
    <a  href="/kustomize/api-reference/kustomization/bases/" class="align-left pl-0 pr-2 collapsed td-sidebar-link td-sidebar-link__section">bases</a>
  </li>
  <ul>
    <li class="collapse " id="kustomizeapi-referencekustomizationbases">
      
      
      
    </li>
  </ul>
</ul>

      
      
      
      






<ul class="td-sidebar-nav__section pr-md-3">
  <li class="td-sidebar-nav__section-title">
    <a  href="/kustomize/api-reference/kustomization/commonannotations/" class="align-left pl-0 pr-2 collapsed td-sidebar-link td-sidebar-link__section">commonAnnotations</a>
  </li>
  <ul>
    <li class="collapse " id="kustomizeapi-referencekustomizationcommonannotations">
      
      
      
    </li>
  </ul>
</ul>

      
      
      
      






<ul class="td-sidebar-nav__section pr-md-3">
  <li class="td-sidebar-nav__section-title">
    <a  href="/kustomize/api-reference/kustomization/commonlabels/" class="align-left pl-0 pr-2 collapsed td-sidebar-link td-sidebar-link__section">commonLabels</a>
  </li>
  <ul>
    <li class="collapse " id="kustomizeapi-referencekustomizationcommonlabels">
      
      
      
    </li>
  </ul>
</ul>

      
      
      
      






<ul class="td-sidebar-nav__section pr-md-3">
  <li class="td-sidebar-nav__section-title">
    <a  href="/kustomize/api-reference/kustomization/components/" class="align-left pl-0 pr-2 collapsed td-sidebar-link td-sidebar-link__section">components</a>
  </li>
  <ul>
    <li class="collapse " id="kustomizeapi-referencekustomizationcomponents">
      
      
      
    </li>
  </ul>
</ul>

      
      
      
      






<ul class="td-sidebar-nav__section pr-md-3">
  <li class="td-sidebar-nav__section-title">
    <a  href="/kustomize/api-reference/kustomization/configmapgenerator/" class="align-left pl-0 pr-2 collapsed td-sidebar-link td-sidebar-link__section">configMapGenerator</a>
  </li>
  <ul>
    <li class="collapse " id="kustomizeapi-referencekustomizationconfigmapgenerator">
      
      
      
    </li>
  </ul>
</ul>

      
      
      
      






<ul class="td-sidebar-nav__section pr-md-3">
  <li class="td-sidebar-nav__section-title">
    <a  href="/kustomize/api-reference/kustomization/crds/" class="align-left pl-0 pr-2 collapsed td-sidebar-link td-sidebar-link__section">crds</a>
  </li>
  <ul>
    <li class="collapse " id="kustomizeapi-referencekustomizationcrds">
      
      
      
    </li>
  </ul>
</ul>

      
      
      
      






<ul class="td-sidebar-nav__section pr-md-3">
  <li class="td-sidebar-nav__section-title">
    <a  href="/kustomize/api-reference/kustomization/generatoroptions/" class="align-left pl-0 pr-2 collapsed td-sidebar-link td-sidebar-link__section">generatorOptions</a>
  </li>
  <ul>
    <li class="collapse " id="kustomizeapi-referencekustomizationgeneratoroptions">
      
      
      
    </li>
  </ul>
</ul>

      
      
      
      






<ul class="td-sidebar-nav__section pr-md-3">
  <li class="td-sidebar-nav__section-title">
    <a  href="/kustomize/api-reference/kustomization/images/" class="align-left pl-0 pr-2 collapsed td-sidebar-link td-sidebar-link__section">images</a>
  </li>
  <ul>
    <li class="collapse " id="kustomizeapi-referencekustomizationimages">
      
      
      
    </li>
  </ul>
</ul>

      
      
      
      






<ul class="td-sidebar-nav__section pr-md-3">
  <li class="td-sidebar-nav__section-title">
    <a  href="/kustomize/api-reference/kustomization/nameprefix/" class="align-left pl-0 pr-2 collapsed td-sidebar-link td-sidebar-link__section">namePrefix</a>
  </li>
  <ul>
    <li class="collapse " id="kustomizeapi-referencekustomizationnameprefix">
      
      
      
    </li>
  </ul>
</ul>

      
      
      
      






<ul class="td-sidebar-nav__section pr-md-3">
  <li class="td-sidebar-nav__section-title">
    <a  href="/kustomize/api-reference/kustomization/namespace/" class="align-left pl-0 pr-2 collapsed td-sidebar-link td-sidebar-link__section">namespace</a>
  </li>
  <ul>
    <li class="collapse " id="kustomizeapi-referencekustomizationnamespace">
      
      
      
    </li>
  </ul>
</ul>

      
      
      
      






<ul class="td-sidebar-nav__section pr-md-3">
  <li class="td-sidebar-nav__section-title">
    <a  href="/kustomize/api-reference/kustomization/namesuffix/" class="align-left pl-0 pr-2 collapsed td-sidebar-link td-sidebar-link__section">nameSuffix</a>
  </li>
  <ul>
    <li class="collapse " id="kustomizeapi-referencekustomizationnamesuffix">
      
      
      
    </li>
  </ul>
</ul>

      
      
      
      






<ul class="td-sidebar-nav__section pr-md-3">
  <li class="td-sidebar-nav__section-title">
    <a  href="/kustomize/api-reference/kustomization/patches/" class="align-left pl-0 pr-2 collapsed td-sidebar-link td-sidebar-link__section">patches</a>
  </li>
  <ul>
    <li class="collapse " id="kustomizeapi-referencekustomizationpatches">
      
      
      
    </li>
  </ul>
</ul>

      
      
      
      






<ul class="td-sidebar-nav__section pr-md-3">
  <li class="td-sidebar-nav__section-title">
    <a  href="/kustomize/api-reference/kustomization/patchesjson6902/" class="align-left pl-0 pr-2 collapsed td-sidebar-link td-sidebar-link__section">patchesJson6902</a>
  </li>
  <ul>
    <li class="collapse " id="kustomizeapi-referencekustomizationpatchesjson6902">
      
      
      
    </li>
  </ul>
</ul>

      
      
      
      






<ul class="td-sidebar-nav__section pr-md-3">
  <li class="td-sidebar-nav__section-title">
    <a  href="/kustomize/api-reference/kustomization/patchesstrategicmerge/" class="align-left pl-0 pr-2 collapsed td-sidebar-link td-sidebar-link__section">patchesStrategicMerge</a>
  </li>
  <ul>
    <li class="collapse " id="kustomizeapi-referencekustomizationpatchesstrategicmerge">
      
      
      
    </li>
  </ul>
</ul>

      
      
      
      






<ul class="td-sidebar-nav__section pr-md-3">
  <li class="td-sidebar-nav__section-title">
    <a  href="/kustomize/api-reference/kustomization/replicas/" class="align-left pl-0 pr-2 collapsed td-sidebar-link td-sidebar-link__section">replicas</a>
  </li>
  <ul>
    <li class="collapse " id="kustomizeapi-referencekustomizationreplicas">
      
      
      
    </li>
  </ul>
</ul>

      
      
      
      






<ul class="td-sidebar-nav__section pr-md-3">
  <li class="td-sidebar-nav__section-title">
    <a  href="/kustomize/api-reference/kustomization/resources/" class="align-left pl-0 pr-2 collapsed td-sidebar-link td-sidebar-link__section">resources</a>
  </li>
  <ul>
    <li class="collapse " id="kustomizeapi-referencekustomizationresources">
      
      
      
    </li>
  </ul>
</ul>

      
      
      
      






<ul class="td-sidebar-nav__section pr-md-3">
  <li class="td-sidebar-nav__section-title">
    <a  href="/kustomize/api-reference/kustomization/secretegenerator/" class="align-left pl-0 pr-2 collapsed td-sidebar-link td-sidebar-link__section">secretGenerator</a>
  </li>
  <ul>
    <li class="collapse " id="kustomizeapi-referencekustomizationsecretegenerator">
      
      
      
    </li>
  </ul>
</ul>

      
      
      
      






<ul class="td-sidebar-nav__section pr-md-3">
  <li class="td-sidebar-nav__section-title">
    <a  href="/kustomize/api-reference/kustomization/vars/" class="align-left pl-0 pr-2 collapsed td-sidebar-link td-sidebar-link__section">vars</a>
  </li>
  <ul>
    <li class="collapse " id="kustomizeapi-referencekustomizationvars">
      
      
      
    </li>
  </ul>
</ul>

      
      
    </li>
  </ul>
</ul>

      
      
      
      






<ul class="td-sidebar-nav__section pr-md-3">
  <li class="td-sidebar-nav__section-title">
    <a  href="/kustomize/api-reference/glossary/" class="align-left pl-0 pr-2 active td-sidebar-link td-sidebar-link__section">Glossary</a>
  </li>
  <ul>
    <li class="collapse show" id="kustomizeapi-referenceglossary">
      
      
      
    </li>
  </ul>
</ul>

      
      
    </li>
  </ul>
</ul>

  </nav>
</div>




          </div>
          <div class="d-none d-xl-block col-xl-2 td-toc d-print-none">
            






<div class="td-page-meta ml-2 pb-1 pt-2 mb-0">





<a href="https://github.com/kubernetes-sigs/kustomize/edit/master/site/content/en/api-reference/glossary/_index.md" target="_blank"><i class="fa fa-edit fa-fw"></i> Edit this page</a>
<a href="https://github.com/kubernetes-sigs/kustomize/issues/new?title=Glossary" target="_blank"><i class="fab fa-github fa-fw"></i> Create documentation issue</a>


<a href="https://github.com/kubernetes-sigs/kustomize/issues/new" target="_blank"><i class="fas fa-tasks fa-fw"></i> Create project issue</a>

</div>






<nav id="TableOfContents">
  <ul>
    <li><a href="#application">application</a></li>
    <li><a href="#apply">apply</a></li>
    <li><a href="#base">base</a></li>
    <li><a href="#bespoke-configuration">bespoke configuration</a></li>
    <li><a href="#custom-resource-definition">custom resource definition</a></li>
    <li><a href="#declarative-application-management">declarative application management</a></li>
    <li><a href="#generator">generator</a></li>
    <li><a href="#gitops">gitops</a></li>
    <li><a href="#kustomization">kustomization</a></li>
    <li><a href="#kustomization-root">kustomization root</a></li>
    <li><a href="#kubernetes">kubernetes</a></li>
    <li><a href="#kubernetes-style-object">kubernetes-style object</a></li>
    <li><a href="#kustomize">kustomize</a></li>
    <li><a href="#off-the-shelf-configuration">off-the-shelf configuration</a></li>
    <li><a href="#overlay">overlay</a></li>
    <li><a href="#package">package</a></li>
    <li><a href="#patch">patch</a></li>
    <li><a href="#patchstrategicmerge">patchStrategicMerge</a></li>
    <li><a href="#patchjson6902">patchJson6902</a></li>
    <li><a href="#plugin">plugin</a></li>
    <li><a href="#resource">resource</a></li>
    <li><a href="#root">root</a></li>
    <li><a href="#sub-target--sub-application--sub-package">sub-target / sub-application / sub-package</a></li>
    <li><a href="#target">target</a></li>
    <li><a href="#transformer">transformer</a></li>
    <li><a href="#variant">variant</a></li>
  </ul>
</nav>



          </div>
          <main class="col-12 col-md-9 col-xl-8 pl-md-5" role="main">
            
  

            <nav aria-label="breadcrumb" class="d-none d-md-block d-print-none">
	<ol class="breadcrumb spb-1">
		







<li class="breadcrumb-item" >
	<a href="https://kubernetes-sigs.github.io/kustomize/api-reference/">API Reference</a>
</li>




<li class="breadcrumb-item active" aria-current="page">
	<a href="https://kubernetes-sigs.github.io/kustomize/api-reference/glossary/">Glossary</a>
</li>

	</ol>
</nav	>

            
<div class="td-content">
	<h1>Glossary</h1>
	<div class="lead">Glossary of terms</div>
	<h1 id="glossary">Glossary</h1>
<h2 id="application">application</h2>
<p>An <em>application</em> is a group of k8s resources related by
some common purpose, e.g.  a load balancer in front of a
webserver backed by a database.
<a href="#resource">Resource</a> labelling, naming and metadata schemes have
historically served to group resources together for
collective operations like <em>list</em> and <em>remove</em>.</p>
<p>This <a href="https://github.com/kubernetes/community/pull/1629">proposal</a> describes a new k8s resource called
<em>application</em> to more formally describe this idea and
provide support for application-level operations and
dashboards.</p>
<p><a href="#kustomize">kustomize</a> configures k8s resources, and the proposed
application resource is just another resource.</p>
<h2 id="apply">apply</h2>
<p>The verb <em>apply</em> in the context of k8s refers to a
kubectl command and an in-progress <a href="https://goo.gl/UbCRuf">API
endpoint</a> for mutating a
cluster.</p>
<p>One <em>applies</em> a statement of what one wants to a
cluster in the form of a complete resource list.</p>
<p>The cluster merges this with the previously applied
state and the actual state to arrive at a new desired
state, which the cluster&rsquo;s reconciliation loop attempts
to create.  This is the foundation of level-based state
management in k8s.</p>
<h2 id="base">base</h2>
<p>A <em>base</em> is a <a href="#kustomization">kustomization</a> referred to
by some other <a href="#kustomization">kustomization</a>.</p>
<p>Any kustomization, including an <a href="#overlay">overlay</a>, can be a base to
another kustomization.</p>
<p>A base has no knowledge of the overlays that refer to it.</p>
<p>For simple <a href="#gitops">gitops</a> management, a base configuration
could be the <em>sole content of a git repository
dedicated to that purpose</em>.  Same with <a href="#overlay">overlays</a>.
Changes in a repo could generate a build, test and
deploy cycle.</p>
<h2 id="bespoke-configuration">bespoke configuration</h2>
<p>A <em>bespoke</em> configuration is a <a href="#kustomization">kustomization</a> and some
<a href="#resource">resources</a> created and maintained internally by some
organization for their own purposes.</p>
<p>The <a href="/kustomize/guides">workflow</a> associated with a <em>bespoke</em> config is
simpler than the workflow associated with an
<a href="#off-the-shelf-configuration">off-the-shelf</a> config, because there&rsquo;s no notion of
periodically capturing someone else&rsquo;s upgrades to the
<a href="#off-the-shelf-configuration">off-the-shelf</a> config.</p>
<h2 id="custom-resource-definition">custom resource definition</h2>
<p>One can extend the k8s API by making a
Custom Resource Definition (<a href="https://kubernetes.io/docs/tasks/access-kubernetes-api/custom-resources/custom-resource-definitions/">CRD spec</a>).</p>
<p>This defines a custom <a href="#resource">resource</a> (CD), an entirely
new resource that can be used alongside <em>native</em>
resources like ConfigMaps, Deployments, etc.</p>
<p>Kustomize can customize a CD, but to do so
kustomize must also be given the corresponding CRD
so that it can interpret the structure correctly.</p>
<h2 id="declarative-application-management">declarative application management</h2>
<p>Kustomize aspires to support <a href="https://github.com/kubernetes/community/blob/master/contributors/design-proposals/architecture/declarative-application-management.md">Declarative Application Management</a>,
a set of best practices around managing k8s clusters.</p>
<p>In brief, kustomize should</p>
<ul>
<li>Work with any configuration, be it bespoke,
off-the-shelf, stateless, stateful, etc.</li>
<li>Support common customizations, and creation of
<a href="#variant">variants</a> (e.g. <em>development</em> vs.
<em>staging</em> vs. <em>production</em>).</li>
<li>Expose and teach native k8s APIs, rather than
hide them.</li>
<li>Add no friction to version control integration to
support reviews and audit trails.</li>
<li>Compose with other tools in a unix sense.</li>
<li>Eschew crossing the line into templating, domain
specific languages, etc., frustrating the other
goals.</li>
</ul>
<h2 id="generator">generator</h2>
<p>A generator makes resources that can be used as is,
or fed into a <a href="#transformer">transformer</a>.</p>
<h2 id="gitops">gitops</h2>
<p>Devops or CICD workflows that use a git repository as a
single source of truth and take action (e.g., build,
test or deploy) when that truth changes.</p>
<h2 id="kustomization">kustomization</h2>
<p>The term <em>kustomization</em> refers to a
<code>kustomization.yaml</code> file, or more generally to a
directory (the <a href="#kustomization-root">root</a>) containing the
<code>kustomization.yaml</code> file and all the relative file
paths that it immediately references (all the local
data that doesn&rsquo;t require a URL specification).</p>
<p>I.e. if someone gives you a <em>kustomization</em> for use
with <a href="#kustomize">kustomize</a>, it could be in the form of</p>
<ul>
<li>one file called <code>kustomization.yaml</code>,</li>
<li>a tarball (containing that YAML file plus what it references),</li>
<li>a git archive (ditto),</li>
<li>a URL to a git repo (ditto), etc.</li>
</ul>
<p>A kustomization file contains <a href="fields.md">fields</a>
falling into four categories:</p>
<ul>
<li>
<p><em>resources</em> - what existing <a href="#resource">resources</a> are to be customized.
Example fields: <em>resources</em>, <em>crds</em>.</p>
</li>
<li>
<p><em>generators</em> - what <em>new</em> resources should be created.
Example fields: <em>configMapGenerator</em> (legacy),
<em>secretGenerator</em> (legacy), <em>generators</em> (v2.1).</p>
</li>
<li>
<p><em>transformers</em> - what to <em>do</em> to the aforementioned resources.
Example fields: <em>namePrefix</em>, <em>nameSuffix</em>, <em>images</em>,
<em>commonLabels</em>, <em>patchesJson6902</em>, etc. and the more
general <em>transformers</em> (v2.1) field.</p>
</li>
<li>
<p><em>meta</em> - fields which may influence all or some of
the above.  Example fields: <em>vars</em>, <em>namespace</em>,
<em>apiVersion</em>, <em>kind</em>, etc.</p>
</li>
</ul>
<h2 id="kustomization-root">kustomization root</h2>
<p>The directory that immediately contains a
<code>kustomization.yaml</code> file.</p>
<p>When a kustomization file is processed, it may or may
not be able to access files outside its root.</p>
<p>Data files like resource YAML files, or text files
containing <em>name=value</em> pairs intended for a ConfigMap
or Secret, or files representing a patch to be used in
a patch transformation, must live <em>within or below</em> the
root, and as such are specified via <em>relative
paths</em> exclusively.</p>
<p>A special flag (in v2.1), <code>--load_restrictions none</code>,
is provided to relax this security feature, to, say,
allow a patch file to be shared by more than one
kustomization.</p>
<p>Other kustomizations (other directories containing a
<code>kustomization.yaml</code> file) may be referred to by URL, by
absolute path, or by relative path.</p>
<p>If kustomization <strong>A</strong> depends on kustomization <strong>B</strong>, then</p>
<ul>
<li><strong>B</strong> may not <em>contain</em> <strong>A</strong>.</li>
<li><strong>B</strong> may not <em>depend on</em> <strong>A</strong>, even transitively.</li>
</ul>
<p><strong>A</strong> may contain <strong>B</strong>, but in this case it might be
simplest to have <strong>A</strong> directly depend on <strong>B</strong>&rsquo;s
resources and eliminate <strong>B</strong>&rsquo;s kustomization.yaml file
(i.e. absorb <strong>B</strong> into <strong>A</strong>).</p>
<p>Conventionally, <strong>B</strong> is in a directory that&rsquo;s sibling
to <strong>A</strong>, or <strong>B</strong> is off in a completely independent
git repository, referencable from any kustomization.</p>
<p>A common layout is</p>
<blockquote>
<pre><code>├── base
│   ├── deployment.yaml
│   ├── kustomization.yaml
│   └── service.yaml
└── overlays
    ├── dev
    │   ├── kustomization.yaml
    │   └── patch.yaml
    ├── prod
    │   ├── kustomization.yaml
    │   └── patch.yaml
    └── staging
        ├── kustomization.yaml
        └── patch.yaml
</code></pre></blockquote>
<p>The three roots <code>dev</code>, <code>prod</code> and <code>staging</code>
(presumably) all refer to the <code>base</code> root.  One would
have to inspect the <code>kustomization.yaml</code> files to be
sure.</p>
<h2 id="kubernetes">kubernetes</h2>
<p><a href="https://kubernetes.io">Kubernetes</a> is an open-source
system for automating deployment, scaling, and
management of containerized applications.</p>
<p>It&rsquo;s often abbreviated as <em>k8s</em>.</p>
<h2 id="kubernetes-style-object">kubernetes-style object</h2>
<p>An object, expressed in a YAML or JSON file, with the
<a href="https://kubernetes.io/docs/concepts/overview/working-with-objects/kubernetes-objects/#required-fields">fields required</a> by kubernetes.  Basically just a
<em>kind</em> field to identify the type, a <em>metadata/name</em>
field to identify the particular instance, and an
<em>apiVersion</em> field to identify the version (if there&rsquo;s
more than one version).</p>
<h2 id="kustomize">kustomize</h2>
<p><em>kustomize</em> is a command line tool supporting
template-free, structured customization of declarative
configuration targeted to k8s-style objects.</p>
<p><em>Targeted to k8s means</em> that kustomize has some
understanding of API resources, k8s concepts like
names, labels, namespaces, etc. and the semantics of
resource patching.</p>
<p>kustomize is an implementation of <a href="#declarative-application-management">DAM</a>.</p>
<h2 id="off-the-shelf-configuration">off-the-shelf configuration</h2>
<p>An <em>off-the-shelf</em> configuration is a kustomization and
resources intentionally published somewhere for others
to use.</p>
<p>E.g. one might create a github repository like this:</p>
<blockquote>
<pre><code>github.com/username/someapp/
  kustomization.yaml
  deployment.yaml
  configmap.yaml
  README.md
</code></pre></blockquote>
<p>Someone could then <em>fork</em> this repo (on github) and
<em>clone</em> their fork to their local disk for
customization.</p>
<p>This clone could act as a <a href="#base">base</a> for the user&rsquo;s
own <a href="#overlay">overlays</a> to do further customization.</p>
<h2 id="overlay">overlay</h2>
<p>An <em>overlay</em> is a kustomization that depends on
another kustomization.</p>
<p>The <a href="#kustomization">kustomizations</a> an overlay refers to (via file
path, URI or other method) are called <a href="#base">bases</a>.</p>
<p>An overlay is unusable without its bases.</p>
<p>An overlay may act as a base to another overlay.</p>
<p>Overlays make the most sense when there is <em>more than
one</em>, because they create different <a href="#variant">variants</a> of a
common base - e.g.  <em>development</em>, <em>QA</em>, <em>staging</em> and
<em>production</em> environment variants.</p>
<p>These variants use the same overall resources, and vary
in relatively simple ways, e.g. the number of replicas
in a deployment, the CPU to a particular pod, the data
source used in a ConfigMap, etc.</p>
<p>One configures a cluster like this:</p>
<blockquote>
<pre><code> kustomize build someapp/overlays/staging |\
     kubectl apply -f -

 kustomize build someapp/overlays/production |\
     kubectl apply -f -
</code></pre></blockquote>
<p>Usage of the base is implicit - the overlay&rsquo;s
kustomization points to the base.</p>
<p>See also <a href="#kustomization-root">root</a>.</p>
<h2 id="package">package</h2>
<p>The word <em>package</em> has no meaning in kustomize, as
kustomize is not to be confused with a package
management tool in the tradition of, say, <a href="https://en.wikipedia.org/wiki/APT_(Debian)">apt</a> or
<a href="https://en.wikipedia.org/wiki/Rpm_(software)">rpm</a>.</p>
<h2 id="patch">patch</h2>
<p>General instructions to modify a resource.</p>
<p>There are two alternative techniques with similar
power but different notation - the
<a href="#patchstrategicmerge">strategic merge patch</a>
and the <a href="#patchjson6902">JSON patch</a>.</p>
<h2 id="patchstrategicmerge">patchStrategicMerge</h2>
<p>A <em>patchStrategicMerge</em> is <a href="https://git.k8s.io/community/contributors/devel/sig-api-machinery/strategic-merge-patch.md">strategic-merge</a>-style patch (SMP).</p>
<p>An SMP looks like an incomplete YAML specification of
a k8s resource.  The SMP includes <code>TypeMeta</code>
fields to establish the group/version/kind/name of the
<a href="#resource">resource</a> to patch, then just enough remaining fields
to step into a nested structure to specify a new field
value, e.g. an image tag.</p>
<p>By default, an SMP <em>replaces</em> values.  This is
usually desired when the target value is a simple
string, but may not be desired when the target
value is a list.</p>
<p>To change this
default behavior, add a <em>directive</em>.  Recognized
directives in YAML patches are <em>replace</em> (the default)
and <em>delete</em> (see <a href="https://git.k8s.io/community/contributors/devel/sig-api-machinery/strategic-merge-patch.md">these notes</a>).</p>
<p>Note that for custom resources, SMPs are treated as
<a href="https://tools.ietf.org/html/rfc7386">json merge patches</a>.</p>
<p>Fun fact - any resource file can be used as
an SMP, overwriting matching fields in another
resource with the same group/version/kind/name,
but leaving all other fields as they were.</p>
<p>TODO(monopole): add ptr to example.</p>
<h2 id="patchjson6902">patchJson6902</h2>
<p>A <em>patchJson6902</em> refers to a kubernetes <a href="#resource">resource</a> and
a <a href="https://tools.ietf.org/html/rfc6902">JSONPatch</a> specifying how to change the resource.</p>
<p>A <em>patchJson6902</em> can do almost everything a
<em>patchStrategicMerge</em> can do, but with a briefer
syntax.  See this <a href="https://github.com/kubernetes-sigs/kustomize/tree/master/examples/jsonpatch.md">example</a>.</p>
<h2 id="plugin">plugin</h2>
<p>A chunk of code used by kustomize, but not necessarily
compiled into kustomize, to generate and/or transform a
kubernetes resource as part of a kustomization.</p>
<p>Details <a href="../../guides/plugins">here</a>.</p>
<h2 id="resource">resource</h2>
<p>A <em>resource</em> in the context of a REST-ful API is the
target object of an HTTP operation like <em>GET</em>, <em>PUT</em> or
<em>POST</em>.  k8s offers a REST-ful API surface to interact
with clients.</p>
<p>A <em>resource</em>, in the context of a kustomization, is a
<a href="#kustomization-root">root</a> relative path to a <a href="http://www.yaml.org/start.html">YAML</a> or <a href="https://www.json.org/">JSON</a> file
describing a k8s API object, like a Deployment or a
ConfigMap, or it&rsquo;s a path to a kustomization, or a URL
that resolves to a kustomization.</p>
<p>More generally, a resource can be any correct YAML file
that <a href="https://kubernetes.io/docs/concepts/overview/working-with-objects/kubernetes-objects/#required-fields">defines an object</a>
with a <em>kind</em> and a <em>metadata/name</em> field.</p>
<h2 id="root">root</h2>
<p>See <a href="#kustomization-root">kustomization root</a>.</p>
<h2 id="sub-target--sub-application--sub-package">sub-target / sub-application / sub-package</h2>
<p>A <em>sub-whatever</em> is not a thing. There are only
<a href="#base">bases</a> and <a href="#overlay">overlays</a>.</p>
<h2 id="target">target</h2>
<p>The <em>target</em> is the argument to <code>kustomize build</code>, e.g.:</p>
<blockquote>
<pre><code> kustomize build $target
</code></pre></blockquote>
<p><code>$target</code> must be a path or a url to a <a href="#kustomization">kustomization</a>.</p>
<p>The target contains, or refers to, all the information
needed to create customized resources to send to the
<a href="#apply">apply</a> operation.</p>
<p>A target can be a <a href="#base">base</a> or an <a href="#overlay">overlay</a>.</p>
<h2 id="transformer">transformer</h2>
<p>A transformer can modify a resource, or merely
visit it and collect information about it in the
course of a <code>kustomize build</code>.</p>
<h2 id="variant">variant</h2>
<p>A <em>variant</em> is the outcome, in a cluster, of applying
an <a href="#overlay">overlay</a> to a <a href="#base">base</a>.</p>
<p>E.g., a <em>staging</em> and <em>production</em> overlay both modify
some common base to create distinct variants.</p>
<p>The <em>staging</em> variant is the set of resources exposed
to quality assurance testing, or to some external users
who&rsquo;d like to see what the next version of production
will look like.</p>
<p>The <em>production</em> variant is the set of resources
exposed to production traffic, and thus may employ
deployments with a large number of replicas and higher
cpu and memory requests.</p>

        <div class="section-index">
    
    
    
    
    <hr class="panel-line">
        
            
        
            
        
            
        
            
        
            
        
            
        
            
        
            
        
            
        
            
        
            
        
            
        
            
        
            
        
            
        
            
        
            
        
            
        
            
        
            
        
            
        
    
</div>

	
	
	<div class="text-muted mt-5 pt-3 border-top">Last modified July 16, 2020: <a  href="https://github.com/kubernetes-sigs/kustomize/commit/f9ee578aed600136133c3232fff03029cdfc526e">Docs: Auto-fix markdownlint issues (f9ee578a)</a>
</div>
</div>

          </main>
        </div>
      </div>
      
<footer class="bg-dark py-5 row d-print-none">
  <div class="container-fluid mx-sm-5">
    <div class="row">
      <div class="col-6 col-sm-4 text-xs-center order-sm-2">
        
        
        
<ul class="list-inline mb-0">
  
  <li class="list-inline-item mx-2 h3" data-toggle="tooltip" data-placement="top" title="User mailing list" aria-label="User mailing list">
    <a class="text-white" target="_blank" href="https://groups.google.com/forum/#!forum/kubernetes-sig-cli">
      <i class="fa fa-envelope"></i>
    </a>
  </li>
  
</ul>

        
        
      </div>
      <div class="col-6 col-sm-4 text-right text-xs-center order-sm-3">
        
        
        
<ul class="list-inline mb-0">
  
  <li class="list-inline-item mx-2 h3" data-toggle="tooltip" data-placement="top" title="GitHub" aria-label="GitHub">
    <a class="text-white" target="_blank" href="https://github.com/kubernetes-sigs/kustomize">
      <i class="fab fa-github"></i>
    </a>
  </li>
  
</ul>

        
        
      </div>
      <div class="col-12 col-sm-4 text-center py-2 order-sm-2">
        <small class="text-white">&copy; 2020 Kubernetes Authors All Rights Reserved</small>
        
	
		
	
      </div>
    </div>
  </div>
</footer>


    </div>
    
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" crossorigin="anonymous"></script>







<script src="/kustomize/js/main.min.35b203b3c2114e187f6e4bbf0903c511aaaac5535186321e3b5e364656b6de0c.js" integrity="sha256-NbIDs8IRThh/bku/CQPFEaqqxVNRhjIeO142Rla23gw=" crossorigin="anonymous"></script>



<script src="https://kubernetes-sigs.github.io/kustomize//js/asciinema-player.js"></script>


  </body>
</html>